Conventionally, a navigation device employs a route guidance technique adapted for a traffic lane (such as a High-Occupancy Vehicles (HOV) lane) in which vehicles satisfying specific conditions are allowed to travel. Patent Document 1 describes a technique for such a navigation device. Also, an HOV lane is called a carpool lane.    Patent Document 1: Japanese Unexamined Patent Laid-Open No. 2000-131085